**6.3 Influence of intermeshing**

Intermeshing is a basic concept in pipeline/network planning: it provides intrinsic redundancy for gas delivery in case of trouble/break at single points of pipeline. It supports continuous operation and pressure of the system; as it is most important to keep the whole pipeline system under pressure all the time (if the pressure would drop to zero, oxygen could enter the pipeline system exposing some areas or the system to the risk of explosion). Exaggerated use of intermeshing lead to higher investment cost in pipes and decrease a costefficient network structure in principle (besides, an item of passionate discussions among planners). Intermeshed networks need, because of their complexity, simulation support to get detailed insight into physical state and variables of the pipeline system.
